Crimpable electrical terminals are frequently manufactured in the form of ladder strips. Terminals of this type are stamped and formed from flat strip stock in side-by-side relationship to each other with each terminal being integral at one end, or at both ends, with a carrier strip. Whether a carrier strip is provided along only one side of the terminal of strips or along both sides (in which case each terminal is integral with a carrier strip at both its forward end and its rearward end) will depend on the size of the terminal, the relative thickness of the stock metal, and the precise shape or configuration of the terminal. Where only one carrier strip is provided, the terminals are typically connected to the carrier strip at their rearward end; that is, at the end which is adapted to be crimped on to wires, for the reason that when the terminal is crimped between a pair of crimping dies it should be precisely positioned between the dies. In automatic and semi-automatic crimping machines having means for feeding the strip to position the leading terminal between the dies, more accurate positioning of the rearward end of the leading terminal between the dies can be achieved if this rearward end is rigidly connected to the carrier strip since the carrier strip will hold the rearward end in alignment with the dies whereas the frontal end might be slightly out of alignment if the leading terminal does not extend precisely normally from the carrier strip.
Electrical terminals to be crimped are fed in step-by-step movement to the apparatus integrally attached at one end to an elongate carrier strip, each step of movement of the carrier strip advancing a terminal into position on a stationary anvil of the crimping apparatus. The anvil is typically formed with a front flat surface lying in a general vertical plane and a vertically movable cutter element slides in face-to-face engagement with the front surface of the anvil. The face of the cutter engaged with the anvil is formed with a horizontal slot which slidably receives the carrier strip to properly locate the terminal relative to the anvil and, in a normally maintained rest position, to guide the terminal onto the upper surface of the anvil. A vertically movable die assembly is mounted above the anvil and a terminal is advanced to the anvil by driving the carrier strip forwardly while the die assembly is in a raised position. When the terminal is located on the anvil, a wire is moved into alignment with the terminal and the die assembly is driven downwardly to perform the crimping operation. During this downward movement of the die assembly, the die assembly engages the cutter and drives the cutter downwardly. The carrier strip is trapped within the horizontal slot in the cutter and upon downward movement of the cutter the terminal on the anvil is sheered from the carrier strip along the plane of engagement between the cutter and the vertical front face of the anvil. The die assembly is then raised and the cycle is repeated.
In order to produce a satisfactory mechanical and electrical connection between the wire and the terminal, the wire end, which is to be crimped to the terminal, must be moved into vertical alignment with the U-shaped portion of the terminal so that the wire is centered between the opposed legs of the U-shaped section immediately prior to the crimping of the legs onto the wire. Crimped terminal specifications are becoming increasingly stringent. In order to meet current specifications imposed by customers, it is desirable to achieve a crimped terminal with no missing wire strands and with no trapped wire insulation between the terminal and the wire strands. It is also desirable to eliminate or greatly reduce the amount of scrap terminals produced by a highly automated terminal crimping apparatus. Therefore, it is desirable to be able to measure and determine the accuracy of the crimped terminal to ensure that it is within predetermined guidelines. Furthermore, it is desirable to monitor the crimping operation so that if an automated terminal crimping apparatus does not produce a terminal within specifications, that terminal can be rejected as scrap, and/or the automated terminal crimping apparatus can be shut down for service before producing a large number of scrap crimped terminals.